This invention relates generally to burster apparatus for separating a continuous web into sheets, the separation taking place along transverse, weakened lines. The invention has particular application, for example, to burster apparatus for separating continuous stationery into suitable form sizes.
Prior art paper bursters commonly include a pair of high speed rollers and a pair of low speed rollers between which a paper web passes, the speed differential between the high speed and low speed rollers causing the web to become tightly stretched. The tension built up in the web causes the web to split along a weakened line. Web separation can be assisted by burster means such as a bar or blade positioned at a weakened line. Such a prior art arrangement is disclosed, for example, in U.S. Pat. No. 4,401,249.
In another prior art arrangement, disclosed for example in U.S. Pat. No. 1,437,207, a paper web is clamped on one side of a weakened line, and a bursting tension is applied to the web on the other side of the weakened line so as to bring about a separation of the web along this line.
Such prior art burster arrangements, which rely on the build-up of tension in continuous forms stationery in order to bring about separation along a weakened line, have the disadvantage that improper bursting or tearing of the forms may occur, particularly if the weakened lines are improperly formed.